1. Field of the Invention
The present invention relates to a data processing apparatus for executing an object-oriented operating system, a data processing method implemented with the object-oriented operating system, and a program providing medium which provides a data-processing program for the object-oriented operating system.
2. Description of the Related Art
There is known a technique of applying the object-oriented technology to an operating system and modularizing constituent elements of the operating system into objects. Such an operating system made up of constituent elements modularized into objects is called an object-oriented operating system. An object-oriented operating system, in which an application object executed on an operating system and an object serving as a constituent element of the operating system have a similar execution mechanism, is sometimes called a pure object-oriented operating system.
In an object-oriented operating system, service provided by the operating system is defined by a set of objects. A more flexible operating system than conventional can be constructed by dividing the service in units of object.
More specifically, an object-oriented operating system enables a system in match with user demanded functions to be easily constructed, for example, by appropriately combining objects, which provide the service of the operating system, before the start of execution of the operating system. Also, functions can be added or deleted so as to effect, e.g., optimization or update of a system in a dynamic manner without stopping the system. Thus, an object-oriented operating system is very superior in flexibility of system configuration and easiness of dynamic system changes.
Meanwhile, objects providing the service of an object-oriented operating system are called system objects. The system objects are operated in parallel. Then, the system objects communicate with each other by using a message communication mechanism, exchange messages, and establish synchronous relation among them. Those operations of the system objects increase independence of objects serving as parts of the system, and improve the flexibility of system configuration and the easiness of dynamic system changes. In other words, the flexibility of system configuration and the easiness of dynamic system changes can be improved by realizing a service providing section of the object-oriented operating system in the form of system objects capable of being added and deleted.
As described above, an object-oriented operating system has superior features. The object-oriented operating system however accompanies a problem that if messages are so frequently communicated between objects, the performance in execution of the overall system deteriorates due to an increased communication cost.
System designers of object-oriented operating systems are therefore required to design system objects by not only making use of the superior features of the object-oriented operating system, such as the flexibility of system configuration and the easiness of dynamic system changes, but also giving due consideration to balance between those superior features and the performance in practical execution.